Put a password on a PDF, or take it off

Lock PDF makes a copy that opens only with a password, locked with AES 256, the strongest lock PDFs have.

1. In PDF Tools, tap Lock PDF and choose a PDF.
2. Type a password twice, or tap Suggest one for a strong passphrase.
3. Choose whether people may print it, copy from it, or change it once it's open.
4. Tap Lock PDF. The locked copy is saved to your downloads.

Unlock PDF makes a copy with no password. Type the PDF's password once. It also removes limits on printing or copying from PDFs that open without a password.